Automated License Plate Recognition: The Newest Threat to Your Privacy When You Travel

Law enforcement agencies around the country and across the state have a powerful new tool to effortlessly identify and track you while you drive, and it is a real threat to your privacy.

Automatic License Plate Recognition systems or "ALPR" consist of cameras that are either mounted on a vehicle or a pole. The cameras capture an image of the license plate of every passing vehicle, including cars travelling in the opposite direction and cars parked along the curb. Software then converts the license plate image into text and the system compares the license plate number against a hot list of stolen cars, outstanding warrants, amber alerts, parking violations, suspicious persons, or anything else (we have heard reports of tow truck operators using these devices to identify repos). The hot list database can either be loaded before each shift, or wireless and real time.

When the ALPR matches a license plate, the system notifies the officer, who can immediately pull over the identified vehicle. Regardless of whether there is a match, the system stores the image, license plate number, date, time, and GPS location of every passing vehicle. The newest systems can process one plate per second, or nearly 30,000 plates for every eight-hour shift. A large law enforcement agency with ALPRs installed on even a small percentage of its vehicles could effortlessly record tens of millions of license plates per year.

ALPRs raise serious concerns to your privacy because of the system's ability to monitor and track the movements of ALL vehicles, including those registered to people who are not suspected of any crime. Without restrictions, law enforcement agencies can and do store the data gathered by the license plate readers forever, allowing them to monitor where you have traveled and when you traveled there over an extended period of time. In fact, a key selling point for ALPR vendors is the system’s ability to track drivers. As explained by the Los Angeles Police Department Chief of Detectives, the “real value” of the ALPR “comes from the long-term investigative uses of being able to track vehicles—where they’ve been and what they’ve been doing.” In other words, the cops want to data-mine your driving habits.

ALPR technology has been around for several years, but law enforcement use of the devices has exploded in the past couple of years due to technological advances and significant federal grant money made available. At least 18 Washington law enforcement agencies are using the devices, including the Seattle, Kent and Medina police departments, and the Washington State Patrol currently uses ALPRs at the Seattle and Bainbridge Island ferry terminals, to scan every boarding vehicle.

Currently, Maine and New Hampshire are the only states with laws restricting or limiting ALPR and ALPR data usage. The ACLU of Washington is actively investigating ALPR use in Washington state and will be working to protect your privacy. If you have specific information on how your local police department is using this new technology, please let us know, and keep checking back here for the latest news.